My Lumia 950 XL was working normally and suddenly the second SIM slot stop working. I called few repair stores and they said that the SIM slot is connected directly with the motherboard and sometimes its necessary to replace the motherboard but they said it will be too expensive and not worth it. By the way, I sent my Lumia 950 XL to their official repair center in Hungary and I just got back the phone saying that although my phone is still under warranty, it is not eligible for repair because the SIM card slot issue is not covered by the warranty. Its a mechanical issue and is not covered by the warranty. REALLY MICROSOFT!?!?! After 5 Microsoft Band 2, this thing now with my Lumia 950 XL. I´m done with Microsoft.